将开发过程中常用的内容记录起来，下面的资料是关于C#索引属性使用范例的代码。

using System;public class Document{ public class WordCollection { internal WordCollection(Document d) { document = d; } private bool GetWord(char[] text, int begin, int wordCount, out int start, out int length) { int end = text.Length; int count = 0; int inWord = -1; start = length = 0; for (int i = begin; i <= end; ++i) { bool isLetter = i < end && Char.IsLetterOrDigit(text[i]); if (inWord >= 0) { if (!isLetter) { if (count++ == wordCount) { start = inWord; length = i - inWord; return true; } inWord = -1; } } else { if (isLetter) inWord = i; } } return false; } public string this[int index] { get { int start, length; if (GetWord(document.TextArray, 0, index, out start, out length)) return new string(document.TextArray, start, length); else throw new IndexOutOfRangeException(); } set { int start, length; if (GetWord(document.TextArray, 0, index, out start, out length)) { if (length == value.Length) { Array.Copy(value.ToCharArray(), 0, document.TextArray, start, length); } else { char[] newText = new char[document.TextArray.Length + value.Length - length]; Array.Copy(document.TextArray, 0, newText, 0, start); Array.Copy(value.ToCharArray(), 0, newText, start, value.Length); Array.Copy(document.TextArray, start + length, newText, start + value.Length, document.TextArray.Length - start - length); document.TextArray = newText; } } else throw new IndexOutOfRangeException(); } } public int Count { get { int count = 0, start = 0, length = 0; while (GetWord(document.TextArray, start + length, 0, out start, out length)) ++count; return count; } } } public class CharacterCollection { internal CharacterCollection(Document d) { document = d; } public char this[int index] { get { return document.TextArray[index]; } set { document.TextArray[index] = value; } } public int Count { get { return document.TextArray.Length; } } } public WordCollection Words; public CharacterCollection Characters; public Document(string initialText) { TextArray = initialText.ToCharArray(); Words = new WordCollection(this); Characters = new CharacterCollection(this); } public string Text { get { return new string(TextArray); } }}class Test{ static void Main() { Document d = new Document( "peter piper picked a peck of pickled peppers. How many pickled peppers did peter piper pick?" ); for (int i = 0; i < d.Words.Count; ++i) { if (d.Words[i] == "peter") d.Words[i] = "penelope"; } for (int i = 0; i < d.Characters.Count; ++i) { if (d.Characters[i] == 'p') d.Characters[i] = 'P'; } Console.WriteLine(d.Text); }}